The present invention relates to drive method and/or system for driving a rotary or rotating electric machine, and more specifically to drive method and/or system for driving a rotary electric machine having a plurality of rotors driven by a compound (or composite) current.
Published Japanese Patent Application Kokai No. H11(1999)-356015 discloses a drive method of driving a rotary machine having a coaxial arrangement of a stator and two rotors, by supplying a compound current in the form of a sum of two sinusoidal waves from a (two-level) inverter.